Impact of moisture content and age on the properties of microwaved shelf-stable puffed snacks made from Cheddar cheese

Microwave heating of certain foods (e.g., popcorn) can produce an expanded, puffed structure. During certain baking conditions, some cheeses (e.g., mozzarella) can form expanded structures (e.g., blisters on pizza). However, Cheddar cheese usually melts during heating instead of expanding. Our hypothesis is that by altering the proportions of moisture, protein, and fat content in cheese by drying, perhaps we can achieve a cheese composition or texture more favorable to expansion (i.e., less meltable) during microwave heating. A licensed Wisconsin cheesemaker made 4 batches (n = 4) of Cheddar cheese over a 90-d period. Cylinders (9 mm in height × 13 mm in diameter) were cut from the cheese at 7, 14, 30, 90, and 180 d of age during ripening at 4°C. These cylinders were dried for various periods in a Parmesan drying room (15.5°C, 70% relative humidity, ∼10 m3/min air flow) to make partially dried cheeses with target moisture contents of 20%, 16%, and 12% (and thus, protein contents of 31.2%, 32.9%, and 34.3%, respectively). During heating, none of the partially dried cheese samples melted (loss tangent values w. A split-plot design was used to analyze the impact of the age of the cheese, composition, and their interactions on the properties of the puffs. At 7 d of cheese age, puffs made from cheeses dried to 20% moisture expanded the most, and puffs made from cheeses dried to 12% moisture expanded the least. For cheeses dried to 20% moisture, puff expansion (%) decreased as the age of the cheese (before expansion) increased. Puff texture was assessed by trained sensory panelists (n = 8-10) using a 15-point quantitative descriptive analysis scale and a texture analyzer equipped with an acoustic detector. Sensory hardness and crunchiness of the puffs increased as the moisture content of the dried cheese decreased from 20% to 12%, whereas the quantity of force/sound peaks decreased. Puffs made from cheese dried to 12% moisture achieved higher acoustic peaks (∼90 dB) than puffs made from cheese dried to 20% moisture (∼80 dB). Scanning electron micrographs of the puffed cheeses indicated well-defined strands of protein were observed in puffs made from cheeses dried to 16% and 12% moisture. All partially dried cheeses expanded during microwave heating. We have demonstrated a novel way of making puffed snacks from Cheddar cheese. In our system, increasing the ripening time of cheese and decreasing the moisture content of the dried cheese (which caused a concomitant increase in the protein content) decreased the expansion of the puffs.